The imperial election of 1790 was an imperial election held to select the emperor of the Holy Roman Empire. It took place in Frankfurt on 30 September.
Maximilian III Joseph, the elector of Bavaria, died of smallpox on 30 December 1777, leaving no immediate heirs. He was succeeded by his distant cousin Charles Theodore, then elector of the Electoral Palatinate. Under the provisions of the Peace of Westphalia covering a merger of family lines, the vote of the Palatinate was suppressed, and Charles Theodore, while ruling both territories, would hold one vote as elector of Bavaria.
See main article: War of the Bavarian Succession.
As Charles Theodore also had no immediate legitimate heirs, his cousin Charles II August, the duke of Zweibrücken, was entitled to inherit both Bavaria and the Palatinate. When Charles Theodore, who preferred to live in the Palatinate, offered southern Bavaria to Joseph II, Holy Roman Emperor in exchange for part of the Austrian Netherlands, Charles August objected. He was joined in this objection by Prussia and Saxony, both of whom were wary of any increase in Austrian power in Central Europe. The resulting War of the Bavarian Succession was settled by the Treaty of Teschen of 13 May 1779, which granted the Innviertel to Austria, affirmed Charles Theodore's inheritance of the entire Bavarian electorate, and recognized some Prussian territorial claims.
Joseph died on 20 February 1790. The electors called to Frankfurt to choose his successor were:
Leopold was also king of Hungary and until earlier in the year had been Grand Duke of Tuscany. In the latter role, he had been a reformer and constitutionalist, and his election offered the potential of the spread of similar reforms in Austria and the broader empire.
Leopold was elected and became emperor.